Program transmission over wires



J F. TOOMEY ET AL I PROGRAM TRANSMISSION EVER WIRES m d m q 192g 2 Sheets-Sheet; '1

fI NVENTORS TTORNEY.

5 v Mfl m w W July 6 1926.

- J. F. TOOMEY ET AL PROGRAM TRANSMISSION OVER WIRES 2 Shets-Sheet 2 Filed Nov. 11, 1922 Patented July 6, 1926.

UNITED STATES JOHN F. TOOMEY AND HENRY E. PHELPS, OF YORK, N. Y., ASSIGNORS TO AMERI- CAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YURK.

PROGRAM TRANSMISSION OVER TIRES Application filed November 11, 1922. Serial No. 800,354.

This invention relates to systems of communication and more particularly to systems for disseminating news, information, music or the like.

Various schemes have been proposed heretofore for program transmission. The only one of these-schemes which has beenrxploited to any extent is radio broadcasting,

that is, the broadcasting of news, iutornun.

tion or entertainment by means of radio telephone equipment so that persons pro vided with suitable radio recervmg sets tuned to the proper wave length may receive the transmitted entertaimnent or the like. l

This method, however, has very serious objections. In the tirst place, nuu'arous broadcasting stations in the same area uperate on wave lengths sullicicutly close togcthcr to iuterl'ere with each other. Furthermore, radio telephonic transmission neeessarily "involves the use of a much wider hand of the Frequency spectrum than is used for wireless mil-graph purposes, and in view of the fact that thc numbcr of wave lengths available l'oFradio communication are necessarily limited it is undesirable that wave lengths necessary for couuurrcial communication should be utilized for purposes of more entertainment. Finally, in order to avail himscll ol' thodesired information or cutcrtainmcut, each individual subscriber must provide himself with a radio receiving equipment which involves storing upon his premises exensive storage batteries which are constantly in need of recharging, tonether with a considerable amount of dellrate and elaborate electrical apparatus, such as coils, detectors, amplilicrs, ctc.,. all of which involve careful maintenance. Moreover, the radio receiving set as now known is. at its best, an inherently ugly thing, absolutely out of place in the home and requiring for its operation a network of unslightly wiring.

Realizing the inherent limitations of radio broadcasting, proposals have been made to use existing wire systems, such as telephone, telegraph or power networks for program distribution purposes by transmitting carrier frequencies over such existing power or communication lines. Such a method, how ever, would be. extremely expensive as well as complicated, as it involves a very con-- siderable reorganization of the telephone plant or power plant, and requires the use of quite complicated and expensive apparatus.

The ordinary telephone plant, however, oil'ers unusual facilities for program distribution by the use Qfcrdinary telephonic methods and. without the employment of any high frequency-or carrier methods of signaling. When it is realized that the avcrage suhscribers telephone set is in use for telephonic purposes only during an extrcmely small part of the time it becomesat once apparent that it the telephone line, during its idle periods, could be used for distributing news, information or entertainment, the plant could be used much more economically and the information or the like to be distributed could he'transmitted to the subscriber in the simplest manner possible. It, may further be observed that the average subscriber to a broadcasting service, particularly a service for distributing entertainment, would only desire to avail himscll' of the service during the late afternoon or during the evening, at which times the average subscribers telephone is only used for social purposes and is rarely or never used for business calls.

Having these circumstances in mind, it is proposed by this invention to provide simple, practical and economical arrangements by which news, information, music or other forms of entertainment may be transmitted at ordinary telephonic frequencies from a central program station over subscribers telephone lines. It is also proposed by this invention to provide a system whereby the telephone subscriber they receive the program service without interferin in any Way with the use of his line for ordinary telephone purposes. This invention also renders. available a distribution new) distribution applied to subscrilfaers line involving machine switching the eeri tral ofhce.

Referring to Fig. 1 L designates an ordinary telephone subscribcrs line terminating at one end at a subscribers station A and at the other end in a central ofiice At the station. A, the usual form of telephone set 10 is provided for ordinary telephonic purposes and 'a supplemental leey K is provided for associating with the line a pro gram receiving equipment comprising a. loud speaking receiver 11 and other apparatus to be described later.

At the central station B the line terminotes in the usual type of switching jack J, whereby telephonic communications may be established through the cord circuit C between the line Land other lines terminat ing at the exchange. Normally, the line is disconnected from the jack J and is cone nected to a common program equipment over the contacts of a relay 12 and through a transformer 13, The central rogram distribution equipmentitself is illustrated at D and is of a very simple type, consisting, in its most fundamental form, of an ordinary telephone transmitter and energizing battery, such as is in common. use in telephone substations today.

As the program equipment is normally connected With the line L, the subscriber may avail himself of the service at any time by merely operating the key K at the sub-station, the key K serving to connect the loud speaking receiver 11 to the line through a transformer 14;. At thecentral oflice, in addition to the usual line relay LR, a special. relay SR is bridged across the line, the latter relay operating when the key K is iiCtU. ated to put a busy tone upon the sleeve conductor of the jack Fl to notify the central operator testing the terminal that the subscriber is using the line for receivingthe special service. 'llie line relay LR is marginal and does not operate through the high resistance connection established by the hey K. and will only operate when the line is closed through the low impedance telephone set 10 by taking the receiver from the switchhook.

If the subscriber should desire to use/the line for ordinary telephone purposes"; the line relay LR will operate as soon as the rccciver is taken from the hook to disconnect the line L from the program equipment and connect it to the jack J over the/contacts oi the relay 1?. and operate the line lamp "5. so that the central otiice operator may ablish. the connection in the usual manner means of the cord circuit C. it, upon incoming call, the'operator desires to iblish a connection with the line L, the Lousy tone on the jack J may be disregarded if the subscriber is receiving the program new; .5

nection established by in.-

of the cord C in 'e cl-r @l.

o i s cohort relay i which turn operates the relay 12 to disconnect the line L from the program station. and conne'ct it to the jack :l.

when the hey H 4 current flows trough the bridge, including the subscribel the windings or" the relays and LR atthe centeral station to operate the relay SIS-, the line relay LR not being operated when the set is need for program purposes. The solar relay PB, controls a relay 16, whereby the loud speaking receiver 11 ma be disconnected. from the line, eventhougi the key K is actuated. The polar relay PR is so poled as to energize the relay 16 for this purpose only when. battery is supplied to the line from the cord circuit, the battery connections through the windings of the relays Lift and Slit heina reversed, with respect to the cord circuit. onsequentiy, the relay Fil PR disconnects the loud speaking receiver only when the operator inserts the plug oi? the cord circuit G into the acl-: ll to establish an ordinary telephone ronnec tion. A low resistance relay 1? is in.- cluded in series with the subscribefs set 10, said relay operating to disconnect the polar relay Pit and loud speaking re ceiver 11 from the line L through an auxiliary relay 18 whenever the subscriber takes down the receiver to use his set for ordinary telephonic purposes. This arrange ment is provided so that the program receivin under tese circumstances even though the subscriber should fail to restore the key K.

The detailed operation is as follows: Assuming that the subscriber at station A desires to receive the program service, the key ii. 'is actuated. thereby closing a circuit through the winding of the high resistance polar relay PR, over the normal contacts of the relay 18, over the make contacts of the key K, over the line L, normal contacts of the cut-oil relay 00R and "through the Winding of the special relay Si". and the line relay Lit. The special relay tiltis operated over this circuit but the current flow is not in a direction to operate the relay The relay SR connects a tone to'the s'eeve of the jack '7 to apprise the central oilice operator "when testii'igig the terminal that the subscriber is receiving the disseminated information. The actuation or the hey K serves to'connot the loud r leaking receiver ll "with the over the no real contacts of the relay l6 equipment will be disconnected- 1 ough the transformer 14 and the normal lit the jack .up the relay 16.

If while the line is thus in use, a sulliciently urgent call should come into the central.

switching ottice for the line L, the operator may disregard the busy tone on the sleeve of J and insert the plug of the cord (1 in the jack, which thus completes a circuit over the sleeve of the jackvJ through the cut-oil relay COR. The cut-o1? relay is thereupon energized and at its upper front contact closes a circuit of the switching relay 12 to disconnect the line L from the program station, and connect it to the tip and ring of the jack J. At the same time, the remaining contacts of the cut-off relay COR disconnect the special relay SR and the line relay LR from'the line L. The direct current supplied to the line L through the windings of these relays was not in such a direction as to actuate the high resistance polar relay PR but as soon as the cord circuit is connected to the line and the relays SR and LR disconnected,- the direct current supplied through the cord circuit will be in such a direction as to actuate the polar relay PR to close the circuit of the relay 16, which at once disconnects the loud speaking receiver 11 from the transformer 14. The relay 16 is locked over its right-hand front contact, right-hand back contact of relay 18 and lower. make contact. of key K,- so that said relay 16 will be held up independently of the polar relay, I

The subscriber maynow. be rung in the usual manner by the operator and upon removing the receiver fromv the hook the talking circuit will be established to the central office. Direct current from the central otlice battery flows through the cord circuit over the subscribers line and through the relay 1?, this relay being energized. as long as the receiver is removed from the hook. The relay 17 completes the circuit of the relay 1.8, which disconnects the special receiving apparatus from the line independently of the hey K and at its right-hand contact opens the locking circuit of the relay 16, which is restored to normal. At the end of the con- \crsation, the subscril'icr may hang up his receiver, thereby giving the usual disconnect signal and deenergizing the relay 17, which (it the key K has not been restored) again (oonccts the polar relay PR to the line. (urrcnt flows through polar relay in such a direction as to cuuse it to energize and lock As soon ts. the operator \rilhdrau's the plug of the. cord circuit C from ihcj energized, thereby causing the relay 12 to tail oil and connect the line L to the central program station. The cut-oft relay COR COR nclc J, the cut-oil relay (OR is dc.

also connects the windings of the relays RR and LR to the line, the former being energized to restore the busy tone to the sleeve of the jack J. The direction of the battery current over the line L is now reversed so that the armature of the polar rclay Pit falls oil'. The relay 16 remains locked up however, and it is necessary to key K to unlock the relay 1.6. The key K may then be again actuated if the subscriber desires program service.

If, while the line is being used for rcceiving disseminated information, the subscriber should desire to use the line for establishing-a telephone call the receiver may be removed from the hook, thereby energizing in addition to the already energized relay SR, the line relay LR and the relay 17. The relay 17 actuates relay 18 to disconnect the special receiving equipment independently of the key K and the line relay LR completes the circuit over its inner trout contact for the relay 12. The relay 12 disconnects the line ll from the program slation and connects it to the jack J, while the line lamp 15 is energized over the outer front contact of the marginal line relay LR. The operator will answer the call by inserting the plug of the cord circuit C in the jack J, thereby causing the cut-oil relay to establish a holding circuit for the relay 12 and to disconnect the relays LR and SR from the line as before. At, the end of the conversation, the subscriber may hang up his receiver, and again obtain program reception in the manner already described.

When the subscriber no longer desires to receive the program service he will simply restore the key K, thereby disconnecting the loud speaker and associated apparatus from the line and opening the circuit of the special relay SR. The latter relay will at; once he deenergized and disconnect the busy tone from the jack J.

Fig. 2 illustrates an arrangement for applying the program service to telephone lines tcrn'iinating at a central oflice, etpiippcd for machine, switching. At machine switching otliccs no operators Will be provided to exercise discretion with regard to the urgency of incoming calls, and in practice the circuits might be arranged either to exclude all in coming calls while the special equipment is in use or to permit all incoming calls to interrupt the broadcasting service. The cir cui't illustrated insFig. 2is arranged so that incoming calls will disconnect the program service. The subscriber himself can .intcrrupt the service to make outgoing calls at any time by simply removing his receiver circuit shown in Fig. 1.

t In this form ol" tho invention thecquipment at. the subscribefs station A, both for broadcasting and for ordinary telephonic from the svvitclihook us in the case ol' the restore the 1 o is icleniicel wiil'i thnt shown in 1, except that the subscribers telephone set is provided with the usual form of disl 19 for operating the switching machinery at the central office. The program equip ment at the station D and its association with the line L at the central oiiice is also identical with that illustrated in Fig. l.

The line L terminates at the central ofice for the purpose of establishing incoming connections in the usual form of connector bank (not shown) while for the purpose of establishing outgoing connections the line terminates in the well known heith line switch and its associated master switch. As these elements are Well known in the art only a portion of the circuits thereof are illustrated and the detailed. construction thereof need not bejlescribed. A marginal line relay LR is-pro iclecl as in the manual system, this relay being only operated when the receiver is removed from the switchhoolr. The line relay controls a double wound plunger magnet SP'of well known construction, which performs the double function or acting as a cutoff relay and of operating the plunger P to connect the line to the dial operated switching machine (not shown). A relay 20 is controlled by the plunger magnet SP over one of its cut-off contacts to energize the relay 12, which functions to disconnect the broadcasting equiment from the line. The windings of the p unger mag; net, as is well known, are so arranged that the upper winding, when energized, will reuse the plunger SP to operate. The lower winding, however, will not operate the plunger SP but will hold the plunger SP in operated position if it has been already operated.

Further details of the invention will be understood from the description of the operation which is as follows: Assuming that the subscriber desires to receive disseminated inilorumtion or the like, the key K is actuated to connect the high impedance polar relay PR and the loud speaking reccivcr 11 to the line as before. This establishes a direct current circuit from bati'cry, through the line relay LR, over the upper contact of the plunger magnet PM, iluough uv winding o'fihe retard coil to the lip side of the line L, upper make contact of key K, loft-hand contact of relay 18, winding of polar relay PR, inner right-hand conluct ol. rcluy '18, make cont-act of key K, ring: side of the line L, through the righthund winding of the retard coil at the cenlrul station and over the lower contact of the plunger magnet to ground through the circuits of ihe master switch (not shown). The current flowing through this circuit s not suflicient to operate the line relay LR- and is not in such a direction as to" operate the polar relhy PR. Consequently, the

meme? (lisseminetecl information from the station D is transmitted overihenorinsl contests of relay i2 and ever she line L to the loud speaking receiver 11.

It will be noted that while the line is in this condition no busy poicniiul is applied to. theslceve conductor leading to 'i'hc connector bunk "z t the central oilice. Therefore, if, while gllfi line is being time used, some other subscriber desires to converse with the e scriber on the line L, switching inuchir (not shown) will he operuie f. at the ce tr station in a well known manner in connection wi'lh the lip, ring: end sleeve c \"luctors at ihe cent-rel station, there" neciing ground to the sleeve energize the lower windir cl ihe pl magnet PM. The plunger SP operated over this circuit but the pine magnet operates as u cut-oil relay connect the line relay Lit from the and completes a circuit ior the re ay; ground, through the winding; of s. j over the upper front contact of the pin magnet PM and through the winding of line relay Lil to buttery. The rela 20 is high rcsislance so lhat i'he line c'cluy L? not operated in series therewith, but th lay 2H energized and completes :1 cl for thou-clay 12, whereby the line L is (1 connected from the special equipment at station D and connected with-the lip and ring conductors leading to the connccior bank. Ringingcurrent will now be trunsmittcd from the connector switch in a well 1 known manner lo call the subscriber at A.

The battery supplied to the line through the connector switch will be in he same direction as that supplied through the cord circuit in Fig. l, i. 0.. it will be oi opposite polarity to that supplied through the line relay LR, and if battery current: is connected to the line through the connector switch be fore the first ringing signal is transmitted the polar relay PR will be operated to lock up the relay 1G and disconnect the loud. speaking receiver 11 from the transformer 14. The. subscriber, upon hearing his bell ring, will remove his recci'l'er from the switchhook, thereby con'ipleting circuit through the relay 1?, which energizes relay 18. Relay 18 opens the locking circuit of the relay l6 and at its inner contacts-disconnects the loud speaker and associated equipment from the line independently of the key K. I

At the conclusion of theconverset ion, connector switch will be released in u welh known manner, thereby openingthe circuit over the sleeve conductor for; the lower winding of the plunger magnet, which at once rclcascs, opening the circuit of the re the again to the line L. Assuming that the subscriber at station A has in the meantime machinery at a leading to the connector c3, incisor the contacts oi the relay'12 at the central office, the subscriber at once receives through. the loud speaker 11 the-information or the like which is being transmitted. The con- .dcn ser 23 in the circuit 21, however, preconnects the line relay LR from the line L.

andconnects the line relay in series with the high resistance relay 20. The line relay, being marginal, is not energized in series with the relay 20 but the relay 20 is energized and completes a circuit for the switching relay 12, which disconnects the line L from the program station D and con meets the line to the tip and ring conductors bank. A ringing signal is now transmitted from the connector to the subscriber at A. The latter, upon hearing his bell rin may remove the receiver from the switchhook without disturbing the key K to complete a. connection through his te ephone set, at the same time opening the bridge 21 at contact 22 of the switchhook sothat the loud speaker 11 is no longer effective. At the termination of the conversation the subscriber at A, by the mere act of hanging up his receiver, again completes the bridge circuit 21 so that the loud speaking receiver 11 is again connected to the, line. The release of the switching the central ofiicc removes the ground from the sleeve conductor loading to the connectorbank, thereby denergi'zing the lower winding of the plunger magnet PM and releasing the relay 12 so that the line L is again connected to the station D, and the subscriber at A receives program transmission.

H, while receiving from the program station, the subscriber at A should desire for any reason to make a'telephone call, he may remove the receiver from the switchhoolr as be withoutdisturbing the .key K. The operation of the 'switchhook opens the bridge 21 at contact 22 as before and a low resistance path is established through the subscribers telephone set to operate theline relay LR, as described in connection with Fig. 2. The line relay at its left-hand contact closes a circuit for the relay 12 which disconnects the line 'L from the broadcasting station 1). At its right-hand 'L to the circuits of the t p, ring contact the linerelay Lltcompletesa circuit for the upper. operating winding of the plunger magnet PM, thereby causing the plunger P to be actuated to extend the line selectors (not shown). The operation of the plunger magnet PM also disconnects the line relay LR from the line L and connects it in serice with the high resistance relay 20. [lhis causes the deenergization of the line relay, but relay20 completes a'locking circuit-for the relay 12. The actuation of the plunger .in the meantime has closed a holding circuit through the lower winding of the plunger magnet so'that the plunger is held in actuated position. The subscriber may now matill nipulate his dial 19 to set up the desired call by means of the selector switches (not shown). At the termination of the conversation, the subscriber hangs up his receiver, thereby again oonn'ectin the bridge circuit 21 to the line and opening the low resistance direct current path extendin to a line relay in the connector switch (not shown). This causes the release of the switching machine, thereby disconnecting ground from the release conductor and opening the circuit through the holding winding of the plunger magnet PM. This releases the plunger and restores the circuits to their normal condition so' that the relay 12 is released and again connects the program station to the line L so that the subscriber can again receive disseminated information or the like. If the subscriber no longer desires to receive program transmission he will open the key ll, thereby disoon-' necting the loud speaking receiver 11 frgm the line L.

*It will be obvious that the general principles herein disclosed may be embodied in many other organizations widely different from those illustrated without departing from the'spirit of the invention as defined in the appended claims at is claimed is:

' 1. In a telephone system, a telephone line terminating atone end in a subscribers-station and at the other end in a central ofiice, a telephone set at the subscribers station, means at said central oiiice for interconnectmg said line with other telephone lines for ordinary telephonic intercommunication, a

special receitjjliig apparatus at the subscribers statio'nndapted to be associated with said line for receiving program transmission, :1 program transmitting station,

means whereby said program station and said special receiving apparatus may be .associated with said line when it is not being used for ordinary telephonic communication, and means to prevent said special re ceiving apparatus from being connected to the linev when itis used for ordinary telephonecommunication.

. the loud speaking receiver .mag

hung up, the line relay LR will not he energized. Relay 20, upon being dcen ergized, opens a circuit of the relay 12, which disconnects the line L from the connector bank and connects it to the program station. The hanging up of the subscribers receiver deenergizes the relay 17, which in turn opens the circuit oi? the relay 18 so that and associated apparatus may be again connected to the line in the manner described in connection with Fig. 1, The information transmitted lirom the program station will new again be received as before.

it, while the soecial receiving apparatus associated with the line by means of the key K so that the loud speaker 11 is being ope 'ated, the subscriber at station A should desire to use the line for ordinary telephone purposes, the subs :riber may remove the re cciver from the switchhook, thereby establishing a l0-' resistance connection over a circuit previously traced through the line relay LR and the relay 17. Relay 17 is energized to complete the circuit from relay 18, thereby disconnecting the loud speaking receiver and associated equipment from the line independently of the key K. The man ginal. line relay Llt is operated over the low resistance circuitthrough the substation set and at its left hand contact con'ipletes a circuit for the relay 12, which disconnects the .ine from the central programstation. Over .s right hand contact the line relay LR completes a circuit through the upper winding of the plunger magnet PM, (the portion of this circuit extending tl'irough the mas 5r switch is not shown). he plunger Si? is actuated by means of he upper winding of the plunger magnet to complete a circuit from the line L over the switches controlled by the plunger magnet to the selector not shown). The plunger magnet, upon h energized, disconnects the line relay from the line and connects the winding of said line relay in scrieswith the relay The line relay LR new oecoines dcenergizcd but the relay pletc a hold lug circuit for the relay The actuation ot the plunger switches completes a circuit fron'i battery through the lower winding ti the plunger magnet and over the inner rightlmud contact of the {flldll switch (the complete circuit not being: shown}; The lower winding of the plunya r 1 remains energised during the entire connectionto hold the plimgcr in actuate ni'lsition. The upper operating winding of the plunger magnet is :lecnergized as was as the ui'l'uature of the line relay falls oil.

The line circuit li having been extended over the contacts ol the Keith line switch under the control. oi the plunger 3? to the tip and ring conductors extending to the selectors (not shown), the subscriber may line 20 is energized to com;

manipulate the dial 19 in a well known manner, thereby transmitting impulses over the line to the switching machinery and establishing the desired connection. At the conclusion of the conversation, the subscriber at station A hangs up his receiver. This causes the release of the switching machinery in a. well known manner and as soon as the switching machinery is released the ground applied through such machinery to the conductor marked Release at thestation B is removed therefrom, thereby opening the holding circuit extending over the inner right-hand contact of the plunger switch to the holding winding of the plunger magnet PM. The plunger magnet is now' deenergized, releasing the plunger SP; which disconnects the line from the switching apparatus. The plunger magnet, upon deenergizing, also connects the line relay LR to the line over the circuit previously described. Relay 17 is deenergized when the receiver is hung and the circuit may be placcd'in con dition for receiving the disseminated information as before.

It the subscriber desires to terminate the reception of disseminated information he merely restores the key K to normal, thereby opening the circuit through the line relay LR and polar relay PR (without producing any circuit changes The loud speaking receiver and associated equipment is now disconnected fromthe line at the c0ntacts of the key K and all of the apparatus is in normal condition.

Fig. 3 illustrates a circuit somewhat similar to that of Fig. 2, but involving a simpler form oil? special receiving organization at thesubscrihers station. The circuit arrangen'ient at the central ollicc is identical with that illustrated in Fig. 2. At the subscribe, ers station the subscribefs set is also substantially the same as illustrated in Fi 2. The program receiving arrangement, however, is a much simpler arrangement commising (assent-hilly the loud speaker 11 connected through a trans'lformer 14 with a clr cult 21, which may be bridged across the line tact 22 on the switchhooh oi" the subscriber's set. The key K in this case is also a single contact key, thus further simplifying the apparatus. I

l urlher details of the invention may be umlerstood from the description of the op eration which as follows: If the subscrib or at .f dcsires to receive information or entertainment transmitted from the station I), he simply operates the key K, thereby cl0slug the bridge through the contact of the key K, transformer 14, condenser 23, contact oi? the switchhook, the transmitter of the subscribers telephone set, and a coni the dial 19. As the program station annually connected to the line L over said program station and said special receiving apparatus may be associated with said line when it isnot being used tor ordinary telephonic communication, and means to prevent said special receiving apparatus from being connected to the line when it is used for ordinary telephone communication.

3. In a telephone system, a subscribers line terminating at one end at a subscribers station and at the olherln a central oliice, a telephone set at said subscribens station, sn'ilchil'ig means at the central ofiice Whereby said telephone line may be interconnected with other telephone lines for ordinary telephonic inlercominunication, a program transmitting station normally connected with said telephone line, and means responsive to an incoming call from said substation for disconnecting said line from said program station and connecting it to said switching means.

4. In a telephone system, a subscribers line teri'ninating at, one end at a subscribers station and at the other in a central ofiice, a

' telephone set at said subscribers station,

switching means at the central ollice whereby said telephone line may be interconnected with other telephone lines for ordinary telephonic intercommunication, a program transmitting statlon normally connected a telephone, set at said subscribers station,

switching means at said central ofiice for interconnccting said line with other lines-for ordinary telephonic intercommunication, .a program transmitting station normally connected to said line, special receiving equipment at the subscribers station for receiving program transmission, means to associate said equipment with the line at the will of the subscriber, and means operating when said telephone set is used for ordinary telcphone purposes to disconnect said special receiving equipment from the line.

6. ha telephone'system, a telephone ine terminating at 21,- subscribers station at one end and at a central otlice at the other end, a telephone set at said subscribers station, switching means at said central otlioe for interconnecting said line with other lines for ordinary telephonic intercommunication, a program transmitting station normally connected to said line, special receiving equipment at the subscribers station for receiving program transmission, means to associate said equipment with ,the line at the will of the subscriber,,and means operating when said telephone set is used for ordinary-telephone purposes to disconnect said-special receiving equipment from the line and to disconnect the line from said program station and connect it to said switching means,

7. In'a telephone system, a telephone line terminating at a subseribers station at one end and in acentral oliice at the other end, a telephone set at said subscribers station, switching means at said-central otlice for intel-connecting said line with other lines for ordinary telephonic intercommunication, a

program transmitting station normally connected to said line, special receiving equipment at the subscribers station for receiving program transmission, means to associate said equipment with the line at the will of the subscriber, and means responsive to the connection of another line to said switching means to disconnect said special receiving,

equipment from said line.

8. In a telephone system, a telephone line terminating at one end at a subscribers station and at the other in a central oliice, a teIe phone set at said subscribers station, switching means at said central oilioe for interconneoting said line with other lines for ordinary telephonic intereommunication, a pro gram transmitting station normally connected to said line, special receiving equipment at the subscribers station for receiving program transmission, means to associate said equipment with the line at the will of the subscriber, means responsive to the connection of another line to said switching means to disconnect said special receiving equipment from said line, and to disconnect said line from said program station and connect it to said switching means.

9. In a telephone system, a telephone line terminating at a subscribers station at one end and at a central otiice at the other end, a telephone set at a said subscribers station, switching means at the central oflice interconnecting said line with other lines for ordinary telephonic intercommunication, a

special receiving arrangement at said suloscribers station for receiving program trans mission, .a program transmitting station,

means in coimee't said special receiving a? miigement and said program station with the line when it is not being used for ordinary telephone pui poses and means associated with said eivihahing means for indicat ing when the line is being; used for program reception.

10. 1111a telephone system, a telephone line tei'ii'iinating at one end at a suhseribefis-sim iioii and at the other end in a centi ai oi'iice,

suhscrihefis set at said subscribers staiion switching means at said central oiiice fol interconnecting g'uid line with other lines for ordinary tciephonic intercomimunication, a program i 'anemitting station adapted to he connected with said line when it is not being used or ordinary telephonic purposes but to he disconnectmi therefrom when it is be" iiig so used, a special receiving arrangementat iihe SHbSCIiiJUX S stati'oi 'i'l'or 1-'eceiving'pro gram transn'iission, a key for associating said -special receiving arrangement with the telephone line, and automatic means operating connecting it to seid. switching means when it is connected with another line for ordinary ieiephonlc iniercommumcation.

in testnnony whereof, We have signed our names to ti 's specification this 10th day of November, 1922.

JOHN F. TQOMEY; 'IQENRY E; PHELPS. 

